1. Technical Field
The present invention relates in general to digital data storage systems and, in particular, to the storing and retrieval of data to and from a recording medium. More particularly, the present invention relates to a parallel read/write circuit and a method thereof for efficient storing/retrieval of data to and from a recording medium.
2. Description of the Related Art
A conventional disk drive typically includes one or more magnetic disk platters mounted for rotation on a hub or spindle. A typical disk drive also includes a transducer head supported by a hydrodynamic air bearing that hovers above each magnetic disc. A drive controller is conventionally utilized for controlling the disk drive based on commands received from a host system. The drive controller controls the disk drive to retrieve information from the magnetic disks and to store information on the magnetic disks.
An electromechanical actuator operates within a negative feedback, closed-loop servo system to position the transducer head. The actuator moves the transducer head radially over the disk surface for track seek operations and holds the transducer head directly over a track on the disk surface for track following operations. Information is typically stored in concentric tracks on the surface of the magnetic disks. A number of axially aligned tracks on the disk surfaces are collectively referred to as a cylinder. Data is written to the disk by providing a write signal to one of the transducer heads to encode flux reversals on the surface of the magnetic disk representing the data to be stored. In retrieving data from the disk, the drive controller controls the electromechanical actuator so that the transducer head flies above the magnetic disk, sensing the flux reversals on the magnetic disk and generating a read signal based on those flux reversals. The read signal is typically conditioned and then decoded by the drive controller to recover data represented by flux reversals stored on the magnetic disc and consequently represented in the read signal provided by the transducer head.
In an embedded servo-type system, servo information is recorded on tracks that also contain data stored on the disk drive. The servo data (or servo bursts) are written on the data tracks and are commonly and evenly temporally spaced (or angularly spaced) about the circumference of each track. Data to be stored on the disk drive is written between the servo bursts. Also, some disk surfaces include header information in header fields that are also written on the disk. Header fields correspond to the servo bursts, or may number less than the servo bursts ,i.e., they may correspond to every other servo burst, and so on. As a transducer head reads the servo information, the transducer head provides a position signal which is decoded by a position demodulator and presented in digital form to a servo control processor. The servo control processor compares the actual radial position of the transducer head over the disk (as indicated by the embedded servo burst) with the desired position and commands the actuator to move in order to minimize position error. Additionally, when the host system requests that the disk drive access a new portion of the disk surfaces, the servo control processor controls the disk drive to move the plurality of data heads to an appropriate cylinder to begin accessing the designated disk surface.
In large data throughput environments, such as audio and video environments, random access of the large chunks of data associated with these environments in a rapid fashion presents significant problems. However, conventional disk drive data storage systems typically store and retrieve data to and from a recording medium in a serial manner. That is, data is read and written to and from the recording medium, i.e., disk surfaces, one bit at a time. It is desirable to optimize the rate at which data can be written onto the storage medium, and to optimize the rate at which data can be read from the storage medium.
Accordingly, what is needed in the art is an improved method for optimizing the rate at which data can be written onto the storage medium, and to optimize the rate at which data can be read from the storage medium.
It is therefore an object of the invention to provide an improved method for storing and retrieving data to and from a recording medium.
It is another object of the invention to provide a circuit for parallel reading and writing of data to and from a recording medium.
To achieve the foregoing objects, and in accordance with the invention as embodied and broadly described herein, a parallel read/write circuit for use with a plurality of transducer head assemblies is disclosed. The parallel read/write circuit includes a parallel read/write cache, e.g., a bidirectional parallel-serial converter buffer in one advantageous embodiment. A byte-to-bit disassembler, coupled to the parallel read/write cache, receives parallel data from the parallel read/write cache and transmits each bit of the parallel data to a separate transducer head assembly, where each bit of the parallel data is written onto a different disk surface of a recording medium at substantially the same time. In an advantageous embodiment, the byte-to-bit disassembler is a parallel in/parallel out shift register. The parallel read/write circuit also includes a bit-to-byte assembler, coupled to the parallel read/write cache and the transducer head assemblies, that combines a plurality of data bits into parallel data form, wherein each of the data bits is read from a separate disk surface of the recording medium at substantially the same time. In an advantageous embodiment, the bit-to-byte assembler is a parallel in/parallel out shift register. Alternatively, in another advantageous embodiment, both the bit-to-byte assembler and the byte-to-bit disassembler are the same device.
In another aspect of the present invention, a method for parallel writing of data to a recording medium having a plurality of disk platters, wherein each of the disk platters has at least one magnetic surface, is disclosed. The method includes converting input data designated for storage into a parallel data word size that is equivalent to the number of magnetic surfaces in the recording medium. Next, the parallel data is xe2x80x9cdisassembledxe2x80x9d into its constituent individual bits of data. Subsequently, each of the individual bits of data are then written onto a separate magnetic surface of said recording medium at substantially the same time. Alternatively, in the case of a read operation, a number of data bits are read off the recording medium at substantially the same time, wherein each one of the data bits is read from a separate magnetic surface of the recording medium. The data bits are then combined into a parallel data stream. Next, the parallel data stream is converted into a data format compatible with a requesting system.
The foregoing description has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject matter of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.